Fluid ultraviolet sterilization system

ABSTRACT

The invention provides a fluid UV sterilization system capable of automatically and stably keeping the fluid level, which includes a channel, a UV lamp module group, an electrical controller and a mounting bracket for UV lamp module(s), each UV lamp module comprising a frame and a plurality of UV lamps, the orientation of the frame and the lamps is perpendicular to or forms an angle with the general flow direction in the channel. A baffle is provided on either or both of the upstream and downstream of at least one of the UV lamp module(s), and the bottom of the baffle extends to such an extent towards the bottom of the channel that it at least reaches within the effective radiation distance of the UV lamp module group towards the fluid surface. The fluid UV sterilization system according to the present invention can control the fluid level automatically and stably, and can be used for the sterilization of domestic sewage, industrial sewage, recycled water, tap water and other kinds of water.

CROSS-REFERENCE TO A RELATED APPLICATION

This application is a continuation application of co-pending U.S.application Ser. No. 11/600,608, filed Nov. 16, 2006, which claimspriority to Chinese Application No. 200510125222.7, filed Nov. 18, 2005;both of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The invention relates to fluid ultraviolet (UV) sterilization, and moreparticularly to a fluid UV sterilization system capable of keeping thefluid level automatically.

DESCRIPTION OF RELATED ART

It is well known that a fluid UV sterilization system requires keeping acertain fluid level so as to ensure the sterilization effect. When theflow rate of the fluid increases such that the fluid level goes beyondthe effective radiation distance of the UV sterilization system (saideffective radiation distance means the largest distance between a UVlight source and viruses or bacteria that can be annihilated ordeactivated by the UV light source in the fluid to be sterilized, withthe fluid to be sterilized having a certain transmissivity), part of thefluid will be drained away directly without being effectivelysterilized, thus impairing the overall sterilization effect. Therefore,it is necessary to control the fluid level or the flow rate of the fluidinflow so that the fluid level will not go beyond the effectiveradiation distance of UV lamp module(s) towards the fluid surface, whilestill being not lower than the lowest fluid level limit. Said lowestfluid level limit generally defines the smallest allowable distancebetween the highheat parts of the UV lamps and the fluid surface, so asto ensure that the highheat parts of the UV lamps would not beingexposed to the atmosphere, thereby facilitating the protection of the UVlamps and lengthening their service life as well.

A known technique involves providing at least one overflow gutter on thedownstream of the mounting bracket of the UV lamps, near the end of thechannel, which is also used as an outlet port of the sterilizationsystem. The main body of the overflow gutter is cuboid-shaped, and thetop edge of the gutter is on the same level with the lowest fluid levellimit of the system or is slightly lower than the latter. The gutter hasopenings in one or two of its end portions, which are used as outletopenings communicating with the drainage passage of the sterilizationsystem. When the flow rate increases such that the fluid surface in thechannel becomes higher than the top edge of the gutter, the fluid abovethe top edge will get over said top edge and into the gutter, furtherflows into the drainage passage of the system via the outlet openings ofthe gutter, thereby achieving the purpose of keeping the fluid level. Inthe case where the size and number of said at least one overflow gutterare to be predetermined according to the practical conditions of thesystem, the larger the flow rate or the variation range of the flow rateis, the more overflow gutters are needed with intervals being providedbetween adjacent ones, thus the channel has to be lengthened. Such awell-designed overflow gutter arrangement can keep the fluid levelreliably without the need of any electrical and accessional devices,thus it is of simple structure and easy for maintenance. Furthermore, itcan operate reliably and safely, and consume less energy. However, inthe case where the flow rate or the variation range of the flow rate islarge, in order to ensure the sterilization effect, it is necessary toprovide more overflow gutters for drainage of fluid so that the fluidlevel would not go beyond the effective radiation distance of thesystem. Therefore, the channel has to be considerably lengthened and thecost for construction and land has to be increased, and the drainage offluid is also disadvantageously influenced.

Other techniques involve providing a flap valve or an electrical gate atthe end portion of the channel to control the fluid level. Similarly, inthis case the highest fluid level in the sterilization area should notgo beyond the effective radiation distance of the UV lamp module(s),otherwise, part of the fluid which is beyond the effective radiationdistance would flow out of the channel without receiving sufficient UVradiation, thus impairing the overall sterilization effect. Therefore,for such a system adopting any of the above-mentioned three kinds ofdrainage measures while not using other fluid level control devices atthe same time, it is desirable that the highest fluid level should notgo beyond the effective radiation distance, which leads to a lowdifference value of pressure heads between the inlet end and the outletend of the UV lamp module(s), and a small allowable variation range ofthe flow rate of the fluid inflow. In this system it is not possible toensure that all the fluid in the channel would pass through theeffective radiation area and receive sufficient UV radiation when theflow rate or the variation range of the flow rate is large. Furthermore,since there are a large number of devices in the system, the cost isincreased, and the convenience for assembly and maintenance as well asthe operating reliability are impaired.

Therefore, a UV sterilization system with a simple structure andoccupying less area is needed, which is adapted to the case where theflow rate varies to cause the fluid level in the channel to go beyondthe effective radiation distance, thereby enlarging the allowablevariation range of the flow rate of the fluid inflow. Furthermore, saidsystem is convenient for assembly and maintenance, and can control thefluid level automatically and operate reliably, so as to meet therequirement for sewage treatment.

SUMMARY OF THE INVENTION

Therefore, the object of this invention is to provide a fluid UVsterilization system with a simple structure and occupying less area,which allows for a large variation range of flow rate, and can keep thefluid level automatically and operate reliably.

In order to achieve the above object, the invention provides a fluid UVsterilization system including an electrical controller, a channel, a UVlamp module group consisting of one or more UV lamp module(s), each UVlamp module comprising a frame and a plurality of UV lamps mounted onthe frame; the channel being provided with a fluid level control device,wherein the orientation of the frame of each UV lamp module isperpendicular to or parallel to or forms an angle with the general flowdirection in the channel; a baffle is provided on either the upstream orboth the upstream and downstream of at least one of the UV lampmodule(s), the top of the baffle is higher than the effective radiationdistance of the UV lamp module group towards the fluid surface, and thebottom of the baffle extends to such an extent towards the bottom of thechannel that it at least reaches within the effective radiation distanceof the UV lamp module group towards the fluid surface, and the projectedwidth of the baffle on the channel section perpendicular to the generaflow direction on the upstream of the baffle is equal to the internalwidth of the channel at a place where the baffle is located. In order toimprove the sterilization effect, a baffle can be provided on either orboth of the upstream and downstream of each UV lamp module. It is alsopossible to provide a plurality of baffles outside the UV sterilizationarea in the channel. Said UV lamps are low voltage or medium voltage UVlamps.

Said baffle can be mounted in the following manners:

1. Said baffle is mounted on the UV lamp module(s), extending from thebottom of the mounting bracket towards the bottom of the channel to suchan extent that the bottom of which at least reaches within the effectiveradiation distance of the UV lamp module group towards the fluidsurface;

2. Said baffle is mounted on the bottom of the mounting bracket,extending towards the bottom of the channel to such an extent that thebottom of which at least reaches within the effective radiation distanceof the UV lamp module group towards the fluid surface;

3. Said battle is fixed on the channel.

Said baffle can be a blind plate, or the upper part thereof is blindwhile the lower part thereof has perforations, said perforations arelocated within the effective radiation distance of the UV lamp modulegroup towards the fluid surface.

The UV fluid sterilization system according to the present invention hasthe following advantages:

1. The space above the effective radiation distance of the UV lampmodule(s) towards the fluid surface, between the inlet end and theoutlet end of the channel, can be used as a buffer zone before the fluidflows out, so that the flow direction of the fluid beyond the UVradiation area is changed and it passes through the effective UVradiation area. Therefore, this system is adapted to the case where theinlet flow rate varies such that the fluid level in the channel goesbeyond the effective radiation distance, thus enlarging the allowablevariation range of the inlet flow rate of the system.

2. With the aid of the baffle, the fluid beyond the effective radiationdistance is diverted to pass through the effective UV radiation area, soas to receive sufficient UV radiation, thereby improving thesterilization effect, operating reliability and safety of thesterilization system.

3. Since there are no overflow gutters in the system, the channel can beshortened, the area occupied by the system can be reduced, and thelayout of the sewage treating plant can be simplified, thereby savingthe cost for land and system construction.

4. Since there is no electrical fluid level control device in thesterilization system, the equipment investment as well as energyconsumption can be reduced.

5. The fluid overflows from the system naturally, which facilitateskeeping the fluid level at the outlet end of the channel at a constantheight, thereby the reliability, safety and stability of the system canbe ensured.

6. The baffle is mounted on the mounting bracket for the UV lampmodule(s) or on the frame of the UV lamp module(s) or on the channel,and such a simple structure facilitates the manufacture and assembly ofthe system, thereby reducing the equipment investment and the cost formanufacture, assembly and maintenance.

7. Since the fluid level at the outlet end of the channel is always keptwithin the effective radiation distance of the UV lamp module(s) towardsthe fluid surface and above the highheat parts of the UV lamps duringthe operation of the system, the UV lamps can be effectively protectedand obtain a long service life.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of first embodiment according tothe present invention;

FIG. 2 is a schematic perspective view of the first embodiment accordingto the present invention;

FIG. 3 is a schematic view showing the positional relationship betweenthe UV lamp module(s) and the baffle(s) in second embodiment similar tothe first embodiment; and

FIG. 4 is a schematic plan view of third embodiment according to thepresent invention.

In the figures, an electrical controller is designated by 1; asterilization channel is designated by 2; a UV lamp module group isdesignated by m1; UV lamp module(s) is designated by 3; a frame of theUV lamp module(s) is designated by 301; a mounting bracket for the UVlamp module(s) is designated by 4; mounting slot(s) on the mountingbracket 4 for mounting the UV lamp module(s) is designated by 5;baffle(s) is designated by 6; UV lamp(s) is designated by 7; alight-shielding plate is designated by 8; a fluid level control deviceis designated by 9; the fluid level at the inlet end of the channel isdesignated by H1; the height at the bottom of the baffle(s) isdesignated by H2; the height at the outlet end of the channel isdesignated by H3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

In the first embodiment of the invention, as shown in FIG. 1 and FIG. 2,the fluid to be sterilized flows into the channel 2 from one endthereof, and the other end of the channel 2 is provided with a fluidlevel control device 9 for fluid outflow. The fluid UV sterilizationsystem includes one UV lamp module group m1, which consists of aplurality of UV lamp modules 3, and each of the UV lamp modules 3comprises a frame 301 and a plurality of UV lamps 7 mounted on the frameand arranged parallel to each other. The orientation of the frame ofeach of the UV lamp modules is perpendicular to the general flowdirection in the channel.

The mounting bracket 4 for the UV lamp module group is fixed on thechannel. The mounting bracket 4 is provided with exactly the same numberof mounting slots 5 as that of the UV lamp modules for the mounting ofthe latter. A closed light-shielding plate 8 is provided betweenadjacent mounting slots 5 of the mounting bracket 4 for shielding the UVlight from leaking out of the channel 2. The bottom of thelight-shielding plate 8 of the mounting bracket 4 is provided with thesame number of baffles 6 as that of the UV lamp modules 3. Each baffle 6is disposed on the upstream of each UV lamp module 3. The projectedwidth of each baffle 6 on the channel section perpendicular to thegeneral flow direction on the upstream of each baffle 6 is equal to theinternal width of the channel at a place where each baffle is located,and the thickness of each baffle is equal to or less than the intervalbetween two adjacent modules.

Each baffles 6 extends from the bottom of the mounting bracket 4 towardsthe bottom of the channel to such an extent that the bottom of eachbaffle 6 at least reaches within the effective radiation distance of theUV lamp module group towards the fluid surface. The top of the outletend of the channel is also located within the effective radiationdistance of the UV lamp module group towards the fluid surface. Eachbaffle 6 can be a blind plate, or the upper part thereof is blind whilethe lower part thereof has perforations, which perforations are locatedwithin the effective radiation distance of the UV lamp module group m1towards the fluid surface. Due to the bafflement of each baffle 6, thefluid above the bottom of each baffle 6 is diverted to pass through theeffective UV radiation area below said bottom, so as to receivesufficient UV radiation and achieve a desired sterilization effect. Thesterilized fluid overflows naturally from the top of the outlet end ofthe channel on the downstream of the UV lamp module group m1. It is alsopossible to dispose a baffle 6 on the downstream of each UV lamp module3. In this embodiment, each UV lamp module is provided with one baffle.

As shown in FIG. 1, it is assumed that the fluid level at the inlet endof the channel is H1, i.e. the highest fluid level on the upstream ofthe UV lamp module group m1 is H1. The height at the bottom of eachbaffle 6 is H2 and the height at the top of the outlet end of thechannel is H3. It is possible, through presetting the value of H3, tokeep the fluid level at the outlet end of the channel within theeffective radiation distance of the UV lamp modules towards the fluidsurface, while stilling preventing the highheat parts of the UV lampsfrom being exposed to the atmosphere, such that the sterilized fluidoverflows out naturally. In this embodiment the fluid level controldevice 9 is used as an overflow weir at the outlet end of the channel,such that the sterilized fluid overflows out naturally.

The bottom of each baffle 6 is within the effective radiation distanceof the UV lamp module group m1 towards the fluid surface.

FIG. 3 is a schematic view showing the positional relationship betweenthe UV lamp modules and the baffles in second embodiment similar to thefirst embodiment. The arrangements of the UV lamp modules 3 and thelight-shielding plate are the same as in FIGS. 1 and 2. That is to say,the fluid to be sterilized flows into the channel 2 from one endthereof, and the other end of the channel 2 is provided with a fluidlevel control device 9 for fluid outflow. The mounting bracket 4 of theUV lamp module group is fixed on the channel and provided with exactlythe same number of mounting slots 5 as that of the UV lamp modules forthe mounting of the latter. A closed light-shielding plate 8 is providedbetween adjacent mounting slots 5 of the mounting bracket 4 forshielding the UV light from leaking out of the channel 2. Theorientation of the frame of each UV lamp module is perpendicular to thegeneral flow direction in the channel. As shown in FIG. 3, the mountingbracket 4 and the light-shielding plate 8 of the UV lamp module group,which are the same as in FIG. 1, are omitted, and only two UV lampmodules are illustrated, one of which is shown in lifted state. A baffle6 is respectively provided in front of each of the two UV lamp modules.What differs from FIGS. 1 and 2 is that the UV lamps 7 arranged inparallel on the frame are perpendicular to the fluid surface, while inthe first embodiment the UV lamps 7 are parallel to the fluid surface.Since the UV lamps 7 are perpendicular to the fluid surface, it is notnecessary to lift the modules away the channel as in FIGS. 1 and 2 whenreplacing the UV lamps, thus the workload for replacing the lamps isreduced and the risk of damaging the lamps when lifting the modules awayand resembling them again can also be decreased.

In a third embodiment of the invention, as shown in FIG. 4, four UV lampmodule groups m1, m2, m3, m4 are respectively parallel to orperpendicular to the general flow direction in the channel. In thisembodiment the fluid level control device is used as an overflow weir atthe outlet end of the channel, such that the sterilized fluid overflowsout naturally. As shown in FIG. 4, the fluid inlet end and the fluidoutlet end of the channel 2 are respectively designated by 201 and 202.The walls B and D are both higher than the fluid level in the channel toprevent the fluid from overflowing from the top of the walls B and D.The walls A, C and G are used as outflow weirs 9, and the walls E, F andH are used for mounting the mounting brackets for the UV lamp modules.The walls A, B, C, D, E, F, G and H are all in sealingly contact withthe bottom of the channel.

The arrows in FIG. 4 represent the flow directions of the fluid. Asdescribed in the first embodiment, one baffle can be provided on theupstream or the downstream of each UV lamp module.

When the baffles of the UV lamp module groups m3 and m4 are provided onthe upstream of the respective UV lamp module groups m3 and m4, thewalls E, F and H can either be in sealingly contact with the bottom ofthe channel, or simply serve as mounting supports without sealinglycontacting with the bottom of the channel.

According to the invention, in the case where the flow rate or thevariation range of the flow rate is large, the space higher than theeffective radiation distance of the UV lamp module group towards thefluid surface, between the fluid inlet end and outlet end of thechannel, can be used as a buffer zone before the fluid flows out,thereby the channel need not to be lengthened in order to keep the fluidlevel within the effective radiation distance, while stilling preventingthe high heat parts of the UV lamps from being exposed to theatmosphere, and the sterilized fluid will overflow out naturally.Therefore, the fluid level can be controlled automatically, theprotection of the lamps is facilitated and their service life islengthened.

In the three above-described embodiments, each baffle 6 is providedeither on the bottom of the light-shielding plate 8 of the mountingbracket 4, or on the frame of each UV lamp module. The thickness of eachbaffle is equal to or less than the interval between two adjacentmodules.

It is also possible to fix each baffle 6 on the channel 2, i.e. on thesidewalls or the bottom of the channel. It is desirable to locate thebottom of each baffle 6 within the effective radiation distance of theUV lamp modules towards the fluid surface.

In the first to third embodiments, the orientation of the frame and thebaffle of each UV lamp module 3 is perpendicular to the general flowdirection in the channel, but the frame can also be parallel to or formsan angle with the general flow direction in the channel in practicaluse, as long as the projected width of the baffle on the channel sectionperpendicular to the general flow direction on the upstream of thebaffle is equal to the internal width of the channel at a place wherethe baffle is located. In such case, all the sterilized fluid will flowthrough the effective radiation area of the UV lamp modules, and thefluid level control device is used as an overflow weir at the outlet endor at the side(s) of the channel, such that the sterilized fluidoverflows out naturally.

The orientation of the frame of each UV lamp module may form an anglewith the general flow direction in the channel, in other words, thelongitudinal axis of the UV lamps forms an acute angle with the generalflow direction in the channel.

The fluid UV sterilization system according to the present invention canbe used for the sterilization of domestic sewage, industrial sewage,recycled water, tap water and other kinds of water.

Various modifications and improvements can be envisaged by those skilledin the art, without departing from the spirit and gist of the invention.

1. A fluid UV sterilization system comprising an electrical controller,a channel, a UV lamp module group consisting of one or more UV lampmodule(s), each UV lamp module comprising a frame and a plurality of UVlamps mounted on the frame; the channel being provided with a fluidlevel control device, characterized in that the orientation of the frameof each UV lamp module is perpendicular to or parallel to or forms anangle with the general flow direction in the channel; a baffle isprovided on either the upstream or both the upstream and downstream ofat least one of the UV lamp module(s), the top of the baffle is higherthan the effective radiation distance of the UV lamp module grouptowards the fluid surface, and the bottom of the baffle extends to suchan extent towards the bottom of the channel that it at least reacheswithin the effective radiation distance of the UV lamp module grouptowards the fluid surface, and the projected width of the baffle on thechannel section perpendicular to the general flow direction on theupstream of the baffle is equal to the internal width of the channel ata place where the baffle is located.
 2. The fluid UV sterilizationsystem according to claim 1, characterized in that further including amounting bracket for the UV lamp module(s), the mounting bracket beingfixed on the channel, and the UV lamp module(s) being mounted on themounting bracket.
 3. The fluid UV sterilization system according toclaim 2, characterized in that the baffle is mounted on the bottom ofthe mounting bracket.
 4. The fluid UV sterilization system according toclaim 1, characterized in that the baffle is mounted on the UV lampmodule(s).
 5. The fluid UV sterilization system according to claim 1,characterized in that the baffle is fixed on the channel.
 6. The fluidUV sterilization system according to claim 1, characterized in that thethickness of the baffle is equal to or less than the interval betweentwo adjacent UV lamp modules.
 7. The fluid UV sterilization systemaccording to claim 1, characterized in that the baffle is provided onthe upstream of the UV lamp module group.
 8. The fluid UV sterilizationsystem according to claim 1, characterized in that one baffle isprovided on the upstream of each UV lamp module.
 9. The fluid UVsterilization system according to claim 1, characterized in that onebaffle is provided on the downstream of each UV lamp module.
 10. Thefluid UV sterilization system according to claim 1, characterized inthat one baffle is provided between two adjacent UV lamp modules. 11.The fluid UV sterilization system according to claim 1, characterized inthat the baffle is a blind plate.
 12. The fluid UV sterilization systemaccording to claim 1, characterized in that the upper part of the baffleis blind while the lower part thereof has perforations whichperforations are located within the effective radiation distance of theUV lamp module group towards the fluid surface.
 13. The fluid UVsterilization system according to claim 1, characterized in that thefluid level control device is an overflow weir or a flap valve or anelectrical gate.
 14. The fluid UV sterilization system according toclaim 1, characterized in that the fluid level control device isprovided at the outlet end of the channel.
 15. The fluid UVsterilization system according to claim 1, characterized in that the UVlamps are low voltage or medium voltage UV lamps.